Liquid-cooled cable for electric furnaces and connectors therefor



Feb 13, 1962 R. A. BARRAss LIQUID-COOLED CABLE FOR ELECTRIC FURNACES AND CONNECTORS THEREFOR Original Filed NOV. 30, 1955 2 Sheets-Sheet 1 INVENTOR lz?CH"2DA'ARRAss ATTORNEYS 'I IIIIIIIH z 2 Illlm numb IN, [IW

Feb- 13, 1962 R. A. BARRAss LIQUID-CCCLED CABLE ECR ELECTRIC FURNACES AND CONNECTORS THEREFOR Original Filed. Nov. 50. 1955 2 Sheets-Sheet 2 INVENTOR Plc/MRD ABARR/lss mm ww nw 4 ATTORNEYS United States Patent 2 Claims. (Cl. 174-15) l0 This invention relates to liquid-cooled electr1c cables for electric furnaces and connectors for'such cables, and more particularly to liquid-cooled electric cables and con-y e f nectors for electric phosphorus furnaces and the like.

In the operation of electric furnaces of the type used in the manufacture of elemental phosphorus and the like, it is important that the electrical connectors from the transformer to the furnace electrodes be not only efficient in the transmission of the electric energy but also economical in operation and low in cost. Moreover, it is 20 important that such connectors do notiendanger the safety of the operating personnel. y `Various types of cables and connectors have heretofore been used in industry. For example, the electrical connection between the transformer bus bars andthe elec- 2- trodesr of the furnace has been effected by rigid metal bars which are provided with suitable connector plugs at'both ends. Similarly, flexible metal cables or thin metallic strips, with suitable connector fittings, have been used to permit free movement of the electrodes in a vertical direction relative to the transformer bus bars. In either case, however, these types of cables have serious disadvantages in that uninsulated air-cooled connecting cables radiate considerable heat, are prone to rapid corrosion and oxidation, and' present a serious safety hazard 3 for the operating personnel. Moreover, air-cooled cables have La very limited current-carrying capacity, n wherebythe capacity of the furnace can be substantially limited. f f

To overcome the problem of low current-carrying capacity the cables have been provided with exible metal jackets wherein water or any other suitable ,cooling fluid is circulated. However, whilethe current-carrying capacity of such modified cables is higher than that of air-cooled cables, they are still as much of a safety hazard as exposed air-cooled cables, and are usually very expensive.

The attachment of the ends of the metal cables to the connector plugs has heretofore been accomplished by providing the rearward end of the plugs with wells or recesses wherein the ends of the metal cables are placed and then soldered in place with the aid of silver solder. While this method produces excellent electrical Contact between the cable and the connector plug, the materials involved are costly and the labor required is highly skilled and therefore quite expensive. f

It is one object of the present invention to provide flexible cables for electric furnaces, which have a high current rating.

Another object of this invention is to provide flexible r cables for electric furnaces which do not radiate substan- 60 tial amounts of heat. f

Another object of the present rinvention is to provide flexible cables for electric furnaces wherein the currentcarrying conductors are protected from corrosion and oxidation. 65

Another object of the present invention is to provide flexible insulated cables for electric furnaceswhich do not present safety hazards for operating personnel.

Another object of this invention is to provide simple, inexpensive and yet effective means for attaching con- 0 nector plugs to the ends of metal cables for electric furnaceS. t

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Still anotherobiect of this invention is to provide flexible, liquid-cooled electrical, cable units for use in connection with electric furnaces for the manufacture of elemental phosphorus and the like. l

- Other objects and advantages will `become apparent as the description of the invention proceeds. v f

The above objects are achieved with the aid of the devices and apparatusrshown in the attached drawings, of which: Y

FIG. 1 is a yschematic representation of theelectric furnace, the electrodes, the transformer bus bar, the flexible electric cables and the flow of cooling'liquid through the cables. v

FIG. 2 is a side view of the assembled liquid-cooled cable embodying this invention. l l

FIG. 3 is a sectional view of a connector plug with yattached conductors.

FIG. 4 is a cross-sectional end view of the cable along lines 4 4 of FIG. 3.

FIG. 5 is an end view of the forward end of a connector plug.

FIG. 6 is a side view, in partial section, of a liquidcooled cable with attached connector plugs, embodying n a modification of this invention.

FIG. 7 is a perspective view of a pair'of conductors and a connector plate fastened together in accordance with another embodiment of this invention.

FIG. 8 is a sectional view of the embodiment of FIG.

7 along line 8 8.

Referring to the ydrawings more in detail, and particularly to FIG. 1, the system to which this invention is 'applied consists essentially of a furnace 1, electrodes 2 extending into the furnace, and a transformer or another suitable power source (not shown) comprising bus bars 3. To establish the electrical connection between bus bars 3 and electrodes 2, flexible rubber-jacketed cables 4`are attached at kkone end to connector clamps 5 on the electrodes 2 and at the other end to busbars '3 by means of connector plugs or terminals 6. yCables 4 are; cooled yby a flow of liquid coolant, preferably water, which is circulated from heat exchanger or reservoir 6 vthrough the cables, around the. electrodes through annular passage 32 in clamp 5, and back into the reservoir by a pump 8, as schematically indicated bythe broken lines Aand the arrows in FIG. 1. K n

FIGURES 2, 3, 4 and 5 illustrate the particular struc-` ture of cable 4 of FIG. 1 and the novel method of attaching the cable to terminals 6. (For the purposes of this specification and the claims hereinafter set forth, the term, conductors, shall mean either one or ,more conductors and thus, a cable may be comprised of one or more con-A ductors'.) -Thecable 4 consists of flexible conductors 9 and a flexible insulated hose 10.. The'conductors are made byk and desired conductive metal having a high conductivity, preferably of copper. The flexible insulated hose10 may be made of rubber or plastic material, and

may be coated or uncoated on theoutside surface with asbestos or the like. block the free flow of collingliquid through the cable, the hose 10 may be reinforced with wire 11 embedded in the hose in the form of a spiral or rings. It is preferred that wire 11 be non-magnetic.

Terminals 6 are composed of a forward portion 12 with tapered end 13, a rearward portion 14 and an intermediate portion 15.r The outer surface of tapered portion 13 is preferably provided with a silver coating to insure perfect contact when the terminal is inserted into the corresponding female socket in electrode connector clamps 5 or in bus bars 3. Rearward portion 14 comprises longitudinallyextending grooves or recesses 16 adapted to receive conductors 9 therein.

Cable 4 is attached to terminals 6 by placing the ends of conductors 9 into recesses 16 and clamping the con- To prevent kinking, so as not to ductors in place with the aid of clamping danses l? having grooves or recesses 18 therein. The mechanical pressure required to clamp the conductors in place is produced by bolts 19 and corresponding nuts ,2th ,Flexible hose is attached t0 the. intermediate portion l5 of terminal 6 by band and buckle type Clamping members 21.

A continuous b ore 22 extends from the for-ward end of terminal 6 to the rearward end thereof to permit cooling iiuid to circulate through the cable assembly while the furnace is in operation.

Another embodiment of this invention is shown FIGS. 6 through 8 of the drawings. Flhis embodiment makes use of another very effective and yet inexpensive method o f attaching the conductor to the connector terminals at the electrode end and the bus bar end of the liquid-cooled cable. The cable consists of flexible conductors 9, which in this case are preferably rope lay cables, and a flexible insulated hose lil having spiral or annular wire reinforcement members Il embedded theren in. The conductors 9 are attached to flat plates 23, one pair of conductors to each plate, as shown in FlG. 7. rthe attachment of the conductors to the dat plate is effected by inserting the pair of conductors into a sleeve 24 and then welding the sleeves and the conductors to the plate with the aid of a therniite weld 25. The use of a thermite weld has been found to be a very convenient and efcient way of fastening the conductors to plate 23, but any other suitable method of welding, such as arc welding and the like may also be used. Plates 23 are fastened to the rearward portion 14 of terminal plug 6 by means of bolts 26 and corresponding nuts 27. Hose 10 may be clamped onto intermediate portion l5 of terminal plug 6 with band and buckle type clamping members 2l. Similar to terminal plug 6 in FIG. 3, the terminal plug in the embodiment of FIG. 6 comprises a longitudinal bore 22. to permit the circulation of cooling liquid through the cable assembly.

As a further modification, the terminal plug at the bus bar end of the cable may be constructed as shown in the bottom portion of FIG. 6. In this modification the intermediate and rearward portions of the terminal are substantially identical to the corresponding portions of terminal 6 shown in the upper portion of FIG. 6.v The forward portion 2S, however, is substantially flatin shape. It is inserted between a pair of bus bars 29 and held in place with bolts 30. A bore 31 extends longitudinally through the terminal to allow circulation of the cooling liquid through the cable assembly.

The cooling liquid circulating through the cables de-r scribed herein is preferably water,4 but any other nonecorrosive coolant may, of course, also be used.

The cable assemblies disclosed herein are relatively inexpensive and do not require specially skilled labor for the production thereof. In addition, such cable assemblies contribute to the safety of the operating personnel in that they are insulated over practically their entire length and particularly over that portion of the cable which a workman might contact. Moreover, the current rating is considerably higher than that of the air-cooled liexible cables heretofore employed in conjunction with electric furnaces.

Although it has been stated that the cables according to this invention are particularly adapted for use with electric phosphorus furnaces, it is quite evident that they may readily be employed in conjunction with any electric furnace wherein electric power is transferred from a power source to the furnace electrodes, such as in all types of arc furnaces.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exempliiied in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However, it should be clearly understood that, within the scope of the appended claims, the invention may be practiced by those skilled in the art, and having the benelit of this disclosure, otherwise than as specifically described and exemplified herein.

That which is claimed as patentably novel is:

l. In a liexible liquidcooled electric power transmission cable comprising flexible metal conductors, a flexible insulated hose surrounding said conductors, terminal plugs at the ends of said conductors, said terminal plugs having a forward portion, an intermediate portion, a rearward portion and a continuous longitudinal bore extending through said plugs, and means for removably clamping said hose to said intermediate portion of said terminal plugs, the improvement which consists of metal extensions permanently attached to the ends of said conductors and means for removably fastening said extensions to the rearward portions of said terminal plugs.

2. In a exible liquid-cooled electric power transmis,- sion -cable comprising flexible metal conductors, a flexible insulated hose surrounding said conductors, terminal plugs at the ends of said conductors, said terminal plugs having a forward portion, an intermediate portion, a rearward portion and a continuous longitudinal bore extending through said plugs, and means for removably clamping said hose to said intermediate portion of said terminal plugs, the improvement which consists of metal extensions fused to the ends of Saidv conductors andV means for removably fastening said extensions to the rearward por. tions of said terminal plugs.

References Cited in the file of this patent UNITED STATES PATENTS 2,808,639 Wreford Oct. 8, 1957 

